Combined plating and honing method and apparatus

ABSTRACT

SURFACE TO SIMULTANEOUSLY AND/OR SEQUENTIALLY MECHANICALLY HONE SUCH SURFACE.   A COMBINED PLATING AND HONING METHOD AND APPARAUTS ULTILIZING AND INCORPORATING A ROTATABLE SLEEVE TYPE ANODE AND A PLURALITY OF HONING STONES MOUNTED FOR COAXIAL ROTATION WITH AND RECIPROCATION RELATIVE TO THE SLEEVE TYPE ANODE, THE ANODE BEING ROTATABLE RELATIVE TO A CATHODIC WORK SURFACE TO EFFECT PLATING THEREON AND THE HONING STONES BEING MOVABLE INTO ENGAGEMENT WITH THE PLATED

Aug. 7, 1973 ET AL 3,751,346

COMBINED PLATING AND HONING METHOD AND APPARATUS Filed Aug. 16, 1971 a.M ,7} E

United States Patent O 3,751,346 COMBINED PLATING AND HONING METHOD ANDAPPARATUS Myron P. Ellis, Royal Oak, and Richard J. Gavasso,

Detroit, Mich, assignors to Micromatic Industries, Inc, Detroit, Mich.

Filed Aug. 16, 1971, Ser. No. 172,120

Int. Cl. B23p 1/00, 1/02; C23b 5/56 U.S. Cl. 20426 6 Claims ABSTRACT OFTHE DISCLOSURE BRIEF SUMMARY OF THE INVENTION This invention relates tothe plating and honing arts and, more particularly, to an improvedcombined plating and honing method and apparatus effective to plate asurface of a workpiece and simultaneously and/or sequentiallymechanically hone such surface so as to provide an improved plated andhoned workpiece having an improved surface finish.

Heretofore, various methods and apparatus have been utilized for thepurpose of plating and simultaneously honing the surface of a workpiece.For example, various methods and apparatus have been provided forsimultaneously burnishing and plating a surface of a workpiece while theworkpiece is immersed in a plating solution and the workpiece isfunctioning as an electrical cathode while the honing tool isfunctioning as an electrical anode. For example, such methods andapparatus of the indicated character are disclosed in the U.S.applications of Myron P. Ellis and Richard J. Gavasso Ser. No. 838,113filed July 1, 1969 now Pat. No. 3,616,289, and Ser. No. 864,086 filedOct. 6, 1969 now Pat. No. 3,637,469, and both entitled ElectroplateHoning Method.

An object of the present invention is to overcome disadvantages in priorplating and honing methods and apparatus of the indicated character andto provide an improved combined plating and honing method and apparatusutilizing a rotatable sleeve type anode, positionable in very closeproximity to the workpiece surface, and a plurality of honing stonesmounted for coaxial rotation with and reciprocation relative to thesleeve type anode, the anode being rotatable relative to the workpiecesurface to effect the plating thereof, and the honing stones beingmovable into engagement with the plated surface to simultaneouslymechanically hone such surface during the plating operation, theworkpiece surface being exposed to a pressurized conventional platingsolution during the plating and honing operation.

Another object of the invention is to provide an improved plating andhoning method and improved plating and honing apparatus that areeconomical and commercially feasible to practice and manufacture,durable, eiiicient and reliable in operation.

In accordance with the present invention, an improved honing method andimproved apparatus are provided, the improved method utilizing theimproved apparatus which includes a honing tool that is mounted forcoaxial rotation with and reciprocation relative to a sleeve type anode,the honing tool carrying a plurality of honing stones projectable beyondthe periphery of the sleeve type anode and into engagement with theworkpiece surface. The sleeve type anode is disposed in very close butspaced relationship with respect to the surface of the workpiece and insuch manner that the sleeve acts as an electrical anode and theworkpiece as an electrical cathode, and during high current densityelectroplating, an electrolyte is circulated between the sleeve and theworkpiece whereby metal is deposited on the surface of the workpiece.The sleeve type anode is normally held in an axially fixed positionrelative to the work surface and rotated during the plating operationwhile the honing tool is rotated coaxially with the sleeve type anodeand simultaneously reciprocated during the plating operation 50 as toprovide an improved plated and honed surface having surfacecharacteristics superior to those heretofore obtainable. The improvedhoning method and apparatus may also be utilized to electroplate andsimultaneously hone a semiblind or stepped bore as well as a straightcylindrical bore.

The above as well as other objects and advantages of the presentinvention will become apparent from the following description, theappended claims and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic, elevationalview, with portions in cross-section, of a combined honing and platingmachine embodying the present invention;

FIG. 2 is a cross-sectional view of the structure illustrated in FIG. 1,taken on the line 22 thereof; and

FIG. 3 is a fragmentary, enlarged elevational view of a portion of thestructure illustrated in FIG. 1.

DETAILED DESCRIPTION Referring to the drawings, the present invention isillustrated embodied in apparatus for honing and plating stepped orsemi-blind end and straight cylindrical bores of a workpiece although itwill be understood that the present invention is applicable to otheruses. FIG. 1 illustrates a honing machine, generally designated 10,having a reciprocating quill 12 to which a honing and plating tool,generally designated 14, is drivably connected for reciprocation withthe quill 12 and rotation relative to the quill 12. A work holdingfixture 16 is provided which is mounted beneath the tool 14 asillustrated in FIG. 1 and supports a workpiece 18 in axial alignmentwith the tool 14.

Details of an electrochemical honing machine of a type in which thepresent invention may be incorporated are more fully disclosed in U.S.Pat. No. 3,390,068 issued to M. P. Ellis et al. on June 25, 1968. Itwill be understood that a wide variety of honing tools may be mounted tothe reciprocating quill 12 for both reciprocating and rotationalmovement in any manner well known in the art.

As shown in FIG. 1, the honing and plating tool 14 is positionedrelative to the workpiece 18 for combined plating and honing, theworkpiece 18 being disposed in a fixed position relative to the fixture16 forming a part of the machine 10. The illustrated workpiece 18 has astepped bore 20 in which the lower portion of the bore is partiallyclosed, as at 22. Such a bore may be described generally as a modifiedblind bore but it will be understood that the present invention may alsobe utilized with straight cylindrical bores.

The combined honing and plating tool 14 comprises a tool support 24which includes a plurality of honing stones 26, four of such stones 26being illustrated although any desired number of such honing stones maybe utilized. The stones 26 are mounted relative to the tool support 24so that they may be adjusted radially outwardly or inwardly relative tothe axis of rotation of the tool support in any manner well known in theart whereby the stones may be moved toward and away from the boresurface which is to be plated and honed. One means for moving the honingstones 26 and for supporting them on the tool support 24 is more fullydisclosed in the aforementioned Ellis patent and in US. Pat. No. Re.26,499 issued to J. H. Greening on Dec. 3, 1968. It will be understoodthat any other suitable means may be employed to support and move thehoning stones.

In the embodiment of the invention illustrated, the tool support 24includes an integral flange 25 which is secured to the quill 12 by aretaining ring 27 whereby the tool support reciprocates with the quill12, and the tool support 24 is supported for rotation within the quill12 by hearings such as 29.

Surrounding the honing tool support 24 is a sleeve member 30 which isalso adapted to project into the bore 28. The sleeve 30 is provided withlongitudinally extending slots 32 adapted to receive the honing stones26 so that upon radial adjustment, the stones may protrude through theslots 32 and into engagement with the bore surface 28 with any desiredsurface pressure or they may be retracted out of engagement with thesurface 28. The inside diameter of the sleeve member 30 'alfordssufficient clearance between the sleeve and the honing tool support 24to permit reciprocation or relative movement of the tool supportrelative to the sleeve member 30. The outside diameter of the sleevemember is of a selected size to afford a small clearance with the wallsurface 28 of the bore 20 in the workpiece 18.

As schematically shown in FIG. 1, the quill 12 is adapted to bereciprocated by a conventional piston and cylinder unit 34 mounted onthe machine while the sleeve member 30 is adapted to be releasablyclamped to the quill 12 through the agency of conventional piston andcylinder units 36 and 38 for selective reciprocation with the toolsupport 24. The pistons of the piston and cylinder units 36 and 38 areconnected to a flange 39 provided on a bearing collar 40 which supportsthe sleeve 30 while the cylinders of the piston and cylinder units 36and 38 are connected to the opposite ends of an outwardly projecting arm37 fixed to the quill 12. A rotatable drive mechanism, generallydesignated 41, is also provided for simultaneously rotating the toolsupport 24 and the sleeve 30. The rotatable drive mechanism 41 iscomprised of a driving cage 42 which may be rotated about the axis ofthe quill 12 by any suitable rotating driving mechanism such 'as asplined gear drive (not shown). The cage 42 includes angularly spaced,vertically extending driving members, such as 44 and 46, the lower endportions of which are fixed to an integral flange 48 provided on thesleeve 30, as by bolts 50, while the upper end portions of the drivingmembers 44 and 46 are driven by the aforementioned driving mechanism.The driving members 44 and 46 define longitudinally extending slots 52and 54, respectively, in which are mounted rollers, such as 56 and 58,the rollers 56 and 58 in turn being fixed to the tool support 24. Withsuch a construction, rotation of the drive members 44 and 46 impartssimultaneous rotation to both the tool support 24 and the sleeve 30, thesleeve 30 being supported for rotation by bearings 60 and 62 carried bythe bearing collar 40. In addition, the tool support 24 is permitted tobe reciprocated independently of the sleeve 30 through the agency of thepiston and cylinder unit 34 and the sleeve 30 is permitted to bereciprocated with the tool support 24 by actuating the piston andcylinder units 36 and 38 so that the arm 37, the flange 48 of the sleeve30 and the bearing collar 40 are clamped together for reciprocation withthe quill 12. Thus, such a construction either permits the rotating toolsupport 24 to move vertically relative to the simultaneously rotatingbut longitudinally stationary sleeve 30 within the range afforded by thelength of the slots 32, or both the tool support 24 and sleeve 30 may besimultaneously reciprocated.

The lower end of the collar 40 is insulated from the fixture 16 by aninsulator 64 made of any suitable electrically non-conductive material,the insulator 64 remaining stationary relative to the fixture 16 whilepermitting rotational and reciprocable movement of the sleeve member 30.

As is well known, it is necessary during plating to pro- 10 vide anelectrolyte or plating solution in the area between the tool and thework surface to be plated. As shown in FIG. 1, the flow path or circuitby which plating solution may be circulated, includes a reservoir 66 ofelectrolytic solution which is pumped by means of a pump 68 through aconduit 70 to a port 72 in the fixture 16 and thereafter through passage74 into the lower end 76 at the semi-blind bore 20. The plating solutionis free to flow through the enlarged radial bore portion 77 and throughthe annular space formed by the outer diameter of the sleeve member 30and the bore surface 28 of the workpiece to a passageway 78 provided atthe upper end of the fixure 16. The plating solution flows from thepassageway 78 through a conduit 80 which returns the plating solution tothe reservoir 66. In order to prevent reverse flow through the system, acheck valve 82 is provided in the conduit 70 and a pressure gauge 84 maybe provided if desired.

in order to seal the plating solution within the system,

a seal 86 is provided at the upper end of the fixture 16 for engagementwith the outside diameter of the rotating sleeve member 30. Another seal88 is provided which is located between the inner diameter of the sleevemember and the outer diameter of the tool support 24. A

static seal 90 is also provided between the stationary fixture 16 andthe upper surface of the workpiece 18 while the lower portion of theworkpiece is sealed relative to the supporting fixture by means of theseal 92. V The plating solution acts to form an electrically conductivepath between the electrically conductive sleeve member 30 and theelectrically conductive workpiece 18. As shown in FIG. 1, a power supply94 of direct current is provided adjacent the honing machine 10 and isprovided with positive and negative output terminals 96 and 98. Thepower supply unit functions to supply direct electric current of aselected magnitude to the work environment. The positive output terminal96 is connected by a conductor 100 to a brush take-otf unit 102 by meansof which the electric current may be transmitted between the powersource and the sleeve member 30 during rotation of the latter. From thesleeve member, the current flows through the electrolyte to theworkpiece 18 which is of electrically conductive material. A conductor104 between the workpiece and the negative terminal of the power supplyunit completes the electrical circuit.

Thus far the invention has been described in connection with operationson a workpiece with a modified blind bore. It will be understood,however, that the invention may be employed to hone and plate an openended or straight cylindrical bore in a workpiece. In this instance, thefixture may be provided with an enlarged inlet passageway to eliminateany restriction to the free flow of plating solution into the bore ofthe workpiece during the plating and honing process.

In operation, the apparatus 10 is employed for honing and electroplatingby first retracting the quill 12 together with the honing-plate tool 14to its uppermost position.

A workpiece 18 is then positioned in the fixture 16 so that theworkpiece bore 20 is in axial alignment with the axis of rotation of thetool 14. With the honing stones 26 retracted within the slots 32 of thesleeve member 30,

the tool support 24 and sleeve member 30 are moved as a unit verticallydownward until the lower end of the sleeve 30 is located at a positionnear the lower end of the modified stepped bore as shown in FIGS. 1 and2 after which the sleeve 30 is unclamped from the quill 12 by releasingthe piston and cylinder units 36 and 38. With the combined honing andplating tool 14 in this position, the flow of plating solution isinitiated to cause fluid flow between the outer surface of the sleevemember 30 and the bore surface 28 of the workpiece. Thereafter, thehoning stones are brought into engagement with the surface 28 and thetool support 24 is reciprocated by the piston and cylinder unit 34 andboth the tool support 24 and sleeve 30 are rotated through the agency ofthe drive mechanism 41 to cause an abrading action to take place betweenthe honing stones and the work surface. After a desired degree ofabrading has taken place, the work surface will be sufliciently cleanand be prepared for the subsequent plating cycle.

Thereafter, the electrical current is initiated so that the sleeve 30acts as an anode and the workpiece acts as a cathode and a plating cycleis accomplished during continued rotation of the sleeve member 30 butwith the honing stones 26 retracted slightly to relieve the pressure onthe work surface of the workpiece. Under these conditions and with thecontinued flow of plating solution, plating of the surface 28 iseffected. It will be understood that the DC. current flows in theelectrical circuit previously described and particularly between thesleeve member 30 which acts as an anode, through the electrolyte to theworkpiece which acts as a cathode. As is well known, this causes adepositing of the plating material on the surface 28 of the workpiece.After a sufficient period of time and suflicient depositing and honingof plating material on the work surface 28 of the workpiece, theelectrical current flow may be terminated. If desired, honing may becontinued after the flow of electrical current is terminated.

While preferred embodiments of the invention have been illustrated anddescribed, it will be understood that various changes and modificationsmay be made without departing from the spirit of the invention.

What is claimed is:

1. A method of finishing a surface of an electrically conductivecathodic workpiece with tool means having an electrically conductiveanodic sleeve portion and an abrasive member supported by the tool meansand adjustable outwardly relative to said sleeve portion comprising thesteps of positioning said anodic sleeve portion in predetermined spacedrelationship with respect to the cathodic workpiece, flowing a platingsolution between said surface and said electrically conductive cathodicsleeve portion, passing a direct electrical current between said sleeveportion and said surface through said plating solution to apply metalelectrochemically to said surface, simultaneously rotating said toolmeans and said sleeve portion and reciprocating said tool meansindependently of said sleeve portion so that the metal on said surfaceis abraded, terminating the supply of electrical current, and retractingsaid tool means and sleeve portion from said workpiece.

2. In plating and honing apparatus for plating metal on and removingmetal from a surface defining a bore in an electrically conductivecathodic workpiece, the combination comprising honing tool meanssupported for rotational and reciprocable movement, means for supportingan electrically conductive cathodic workpiece defining a bore coaxiallyaligned with the longitudinal axis of said honing tool means, an anodicsleeve member surrounding said honing tool means and adapted forpositioning in closely spaced relationship to said surface defining saidbore, said sleeve member being provided with at least one longitudinallyextending slot, abrasive means supported on said tool means andprojecting through said slot for movement radially relative to the axisof said tool means into and out of abrading engagement with said boresurface, means for flowing a plating solution between said sleeve memberand said bore surface, means for moving said abrasive means over saidbore surface in a combined reciprocating and rotating motion to removemetal mechanically from said bore surface, means for moving said sleevemember longitudinally in said bore and for maintaining said sleevemember in a fixed longitudinally position in said bore during rotationof said sleeve member, means for passing a direct electric currentbetween said sleeve member to said bore surface through said platingsolution, and means for terminating the supply of direct electriccurrent at the completion of the work cycle.

3. In a combined plating and honing apparatus for removing and platingmetal on a surface defining a bore in an electrically conductivecathodic workpiece, the combination comprising a honing tool, an anodicsleeve formed of electrically conductive material surrounding said tooland defining at least one elongated slot, said sleeve being adapted forpositioning in spaced relationship to a workpiece, abrasive meansmounted on said honing tool and projecting through said slot forabrading engagement with said bore surface of said workpiece, means forflowing a plating solution between said sleeve and said bore surface ofsaid workpiece, means for simultaneously rotating said sleeve and saidabrasive, means for moving said abrasive means in a reciprocating motionindependently of said sleeve to remove metal mechanically from said boresurface, means for passing a direct electric current between said anodicsleeve and said bore surface through said plating solution to applyplating materials to said bore surface, means for terminating the supplyof direct electric current when the bore of said workpiece has beenplated to the desired size, and means for simultaneously retracting saidhoning tool and sleeve at the end of the plating cycle.

4. A combined plating and honing apparatus as delined in claim 3including means for simultaneously rotating said honing tool and sleeve,and means for reciprocating said honing tool and sleeve.

5. A combined plating and honing apparatus as defined in claim 3,wherein said means for passing a direct electric current between saidsleeve and said bore surface includes means for connecting saidworkpiece to one electrical terminal and said sleeve to the otherelectrical terminal of a direct electric current power supply.

6. In combined plating and honing apparatus for removing and platingmetal on a surface defining a bore in an electrically conductiveworkpiece, the combination comprising a honing tool means including asleeve member having an electrically conductive surface, means forsupporting an electrically conductive workpiece with a bore surface in aposition with the longitudinal axis of the bore coaxially aligned withthe longitudinal axis of said sleeve member, abrasive means on said toolmeans adapted for abrading engagement with said bore surface, means forflowing a plating solution between said sleeve member and said boresurface, means for rotating said tool means and reciprocating saidabrasive means independently of said sleeve member while said abrasivemeans is in contact with said bore surface, means for passing a directelectric current between said sleeve member and said bore surfacethrough said plating solution whereby said workpiece is renderd cathodicand said sleeve member is rendered anodic, means for terminating thesupply of direct electric current when the bore has been plated to thedesired size, and means for simultaneously retracting the tool means andsleeve including the abrasive means.

References Cited UNITED STATES PATENTS 3,390,068 1/1968 Ellis et a1204143 G 3,637,469 1/ 1972 Ellis et al. 20426 3,619,401 11/1971 Eisner204217 JOHN H. MACK, Primary Examiner T. 'IUFARIELLO, Assistant ExaminerUS. Cl. X.R.

204-129.46, 217, 224 M, DIG. 10

